In programming languages, an abstract type, unlike Concrete class is a type in a nominative type system which cannot be instantiated. (However, it may have concrete subtypes that do have instances.) An abstract type may have no implementation, or an incomplete implementation. It may include abstract methods or abstract properties that are shared by its subtypes.
A type that is not abstract is called a concrete type.
In many object oriented programming languages, abstract types are known as abstract base classes. In some languages, abstract types with no implementation are known as interfaces. Other names for language features that are (or may be) used to implement abstract types include traits, mixins, flavors, or roles.
Read more about Abstract Type: Signifying Abstract Types, Use of Abstract Types
Famous quotes containing the words abstract and/or type:
“But the abstract conception
Of private experience at its greatest intensity
Becoming universal, which we call “poetry,”
May be affirmed in verse.”
—T.S. (Thomas Stearns)
“Lise: Look, monsieur, I don’t know what type of girl you think I am, but I’m not. And now I would like to return to my friends.
Jerry: I thought you were bored with them. You sure looked it.
Lise: You should see me now.
Jerry: Ouch.”
—Alan Jay Lerner (1918–1986)